Rapid evaluation of food and beverage, such as fish, meat, quality is required in food industry. The biogenic amine content in food has been intensively studied because of their potential toxicity. Histamine is the most biologically active compound from this class, affecting the normal functions of the heart; smooth muscle, motor neurones, and gastric acid secretion. Other biogenic amines, such as putrescine and cadaverine, may amplify the effects caused by histamine intoxication, inhibiting the enzymes involved in histamine biodegradation: diamine oxidase and histamine-N-methyl transferase.
Numerous countries adopted maximum levels for histamine in food, especially in fish products. The Italian law has fixed a level of 100 mg/kg food, and similar limits have been adopted by EEC regulations.
Therefore, there is a need for developing of simple and inexpensive methods for determining of freshness biomarkers. Freshness biomarkers comprising inositol monophosphate, hypoxanthine and xanthine, these are intermediate degradation products of nucleic acids or biogenic amines, which are produced by microbial decarboxylation of the amino acids, histidine, ornithine, and lysine.
Classical methods for the determination of the content of biogenic amines are chromatographic techniques, such as gas chromatography, thin layer chromatography, reversed phase liquid chromatography, and liquid chromatography. However, these often require sample pre-treatment and relatively long analysing time, which leads to high costs and make these methods not suitable for routine use.
From U.S. Pat. No. 5,565,329 is a method for determination of histamine concentration in a sample by determination of the decrease in dissolved oxygen (DO) known. The method involves adding a solution of an enzymatic reagent, which have a histamine oxidase activity, into an examination liquid containing the test sample and detect the sensor output signal. The analyser has a reaction cell provided with a DO electrode. The enzymatic reagent is a Cu-containing fungal amine oxidase. Which is extracted from a cellmass belonging to Aspergillus Niger cultured in a culture medium including amine as a nitrogen source. This approach is not very selective and sensitive.
Enzymatic determination of biogenic amines represents an alternative that can solve the above mentioned problems. However, most of the amino oxidase biosensors require a high operating potential (>500 mV vs. Ag/AgCl), which can lead to high background currents and low selectivity due to bias signals caused by electrochemically easily oxidisable interferences, which are always present in complex matrices, such as food or beverage.